U.S. patent number 10,897,341 [Application Number 14/414,988] was granted by the patent office on 2021-01-19 for detecting intermodulation in broadband communication affecting receiver sensitivity.
This patent grant is currently assigned to Nokia Solutions and Networks Oy. The grantee listed for this patent is Marko Fleischer, Jan Hellmann, Thomas Klink, Eric Koenig, Michael Kronwald. Invention is credited to Marko Fleischer, Jan Hellmann, Thomas Klink, Eric Koenig, Michael Kronwald.
United States Patent |
10,897,341 |
Fleischer , et al. |
January 19, 2021 |
Detecting intermodulation in broadband communication affecting
receiver sensitivity
Abstract
The present invention provides methods, apparatuses and a
program relating to detecting passive intermodulation in broadband
communication. The present invention includes transmitting, at a
base station, a first signal at a first centre frequency and a
second signal at a second centre frequency with a predetermined
transmit power, capturing, at the base station, received signal at
a reception frequency, obtaining, at the base station, a delay
between the transmitted signal and a passive intermodulation caused
received signal.
Inventors: |
Fleischer; Marko (Unterhaching,
DE), Kronwald; Michael (Puchheim, DE),
Klink; Thomas (Ottobrunn, DE), Hellmann; Jan
(Munich, DE), Koenig; Eric (Bernstadt,
DE) |
Applicant: |
Name |
City |
State |
Country |
Type |
Fleischer; Marko
Kronwald; Michael
Klink; Thomas
Hellmann; Jan
Koenig; Eric |
Unterhaching
Puchheim
Ottobrunn
Munich
Bernstadt |
N/A
N/A
N/A
N/A
N/A |
DE
DE
DE
DE
DE |
|
|
Assignee: |
Nokia Solutions and Networks Oy
(Espoo, FI)
|
Appl.
No.: |
14/414,988 |
Filed: |
July 18, 2012 |
PCT
Filed: |
July 18, 2012 |
PCT No.: |
PCT/EP2012/064092 |
371(c)(1),(2),(4) Date: |
May 01, 2015 |
PCT
Pub. No.: |
WO2014/012585 |
PCT
Pub. Date: |
January 23, 2014 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20150358144 A1 |
Dec 10, 2015 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04B
17/19 (20150115); H04W 24/10 (20130101); H04L
41/0677 (20130101); H04B 17/104 (20150115); H04B
17/17 (20150115); H04L 5/143 (20130101) |
Current International
Class: |
H04W
24/10 (20090101); H04L 5/14 (20060101); H04L
12/24 (20060101); H04B 17/17 (20150101); H04B
17/19 (20150101); H04B 17/10 (20150101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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101502007 |
|
Aug 2009 |
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CN |
|
102010033841 |
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Feb 2012 |
|
DE |
|
10 2010 046 099 |
|
Mar 2012 |
|
DE |
|
10-2011-0071722 |
|
Jun 2011 |
|
KR |
|
10-1136994 |
|
Apr 2012 |
|
KR |
|
10-2012-0065127 |
|
Jun 2012 |
|
KR |
|
WO 00/57571 |
|
Sep 2000 |
|
WO |
|
WO-2009082084 |
|
Jul 2009 |
|
WO |
|
WO 2012/009757 |
|
Jan 2012 |
|
WO |
|
Primary Examiner: Phillips; Hassan A
Assistant Examiner: Jones; Prenell P
Attorney, Agent or Firm: Harrington & Smith
Claims
The invention claimed is:
1. A method, comprising: transmitting, at a base station in a
broadband communications system, a first signal at a first center
frequency and a second signal at a second center frequency with a
predetermined transmit power; capturing, at the base station,
received signal at a reception frequency; capturing, at the base
station, a combined transmission signal, where the combined
transmission signal corresponds to the first signal and the second
signal; predicting, at the base station, a passive intermodulation
caused received signal based on the combined transmission signal;
and obtaining, at the base station, a delay between a transmitted
signal and the passive intermodulation caused received signal,
where the transmitted signal comprises the first signal and the
second signal.
2. The method according to claim 1, further comprising: measuring,
at the base station, the delay between the transmitted signal and
the passive intermodulation caused received signal.
3. The method according to claim 1, further comprising: obtaining,
at the base station, the delay between the transmitted signal and
the passive intermodulation caused received signal using
correlation.
4. The method according to claim 1, further comprising: estimating,
at the base station, a fault location within an antenna lineup
based on the obtained delay between the transmitted signal and the
passive intermodulation caused received signal, and a reference
delay between the transmitted signal and its related received
signal, where the related received signal is predicted based, at
least partially, on the transmitted signal.
5. The method according to claim 4, wherein the reference delay
between the transmitted signal and its related received signal is
known in advance.
6. The method according to claim 1, further comprising: measuring,
at the base station, a received signal power of the received signal
at the reception frequency; identifying, at the base station, one
or more passive intermodulation caused received signal power
components in the received signal power using non-linear modeling;
and calculating, at the base station, a difference between the one
or more passive intermodulation caused received signal power
components and the predetermined transmit power.
7. The method according to claim 1, wherein the base station is a
frequency division duplex base transceiver station.
8. An apparatus comprising: a receiver/transmitter configured to
communicate in a broadband communications system with at least
another apparatus, a non-transitory memory configured to store
computer program code, and a processor configured to cause the
apparatus to perform: transmitting a first signal at a first center
frequency and a second signal at a second center frequency with a
predetermined transmit power; capturing received signal at a
reception frequency; capturing a combined transmission signal,
where the combined transmission signal corresponds to the first
signal and the second signal; predicting a passive intermodulation
caused received signal based on the combined transmission signal;
and obtaining a delay between a transmitted signal and the passive
intermodulation caused received signal, where the transmitted
signal comprises the first signal and the second signal.
9. The apparatus according to claim 8, wherein the processor is
configured to cause the apparatus to further perform: measuring the
delay between the transmit signal and the passive intermodulation
caused received signal.
10. The apparatus according to claim 8, wherein the processor is
configured to cause the apparatus to further perform: obtaining the
delay between the transmitted signal and the passive
intermodulation caused received signal using correlation.
11. The apparatus according to claim 8, wherein the processor is
configured to cause the apparatus to further perform: estimating a
fault location within an antenna lineup based on the obtained delay
between the transmitted signal and the passive intermodulation
caused received signal, and a reference delay between the
transmitted signal and its related received signal, where the
related received signal is predicted based, at least partially, on
the transmitted signal.
12. The apparatus according to claim 11, wherein the reference
delay between the transmitted signal and its related received
signal is known in advance.
13. The apparatus according to claim 8, wherein the processor is
configured to cause the apparatus to further perform: measuring a
received signal power of the received signal at the reception
frequency; identifying one or more passive intermodulation caused
received signal power components in the received signal power using
non-linear modeling; and calculating a difference between the one
or more passive intermodulation caused received signal power
components and the predetermined transmit power.
14. The apparatus according to claim 8, wherein the apparatus is a
frequency division duplex base transceiver station.
15. A computer program product embodied on a non-transitory
computer-readable medium in which a computer program is stored
that, when being executed with a computer, is configured to control
an apparatus to: transmit, in a broadband communications system, a
first signal at a first center frequency and a second signal at a
second center frequency with a predetermined transmit power;
capture a received signal at a reception frequency; capture a
combined transmission signal, where the combined transmission
signal corresponds to the first signal and the second signal;
predict a passive intermodulation caused received signal based on
the combined transmission signal; and obtain a delay between a
transmitted signal and the passive intermodulation caused received
signal, where the transmitted signal comprises the first signal and
the second signal.
Description
FIELD OF THE INVENTION
The present invention relates to detecting passive intermodulation
in broadband communication. In particular, the present invention
relates to methods, apparatuses and a program for detecting passive
intermodulation in broadband communication. If in later chapters it
is referred to intermodulation only, intermodulation caused by
passive elements is addressed, also known as PIM.
BACKGROUND OF THE INVENTION
In broadband FDD BTS (frequency division duplex base transceiver
station) receiver architectures, intermodulation
products/distortions are of major concerns and can jeopardize the
receiver performance.
Intermodulation products (PIM) can fall in the own receive band and
degrade the receiver performance. The Intermodulation level depends
on the network performance, equipment and used material, the
transmission power as well as modulation and bandwidth. The
intermodulation characteristic changes over lifetime of the network
(aging) and can today in real sites only be indirectly measured via
KPI (key performance indicator). With broadband products,
intermodulation distortion is becoming more critical.
FIG. 1 is a diagram illustrating occurrence of passive
intermodulation in a network.
Passive intermodulation occurs when in the downlink band two or
more frequencies are used simultaneously. A frequency stemming from
the passive intermodulation can land in the frequency range
dedicated to the uplink channel and thus cause interference and
hence performance degradation to the real uplink signals.
Passive intermodulation (PIM) products are generated by at least
two carriers impinging a non-linear junction. That is, if at least
two frequencies exist in a non-linear device, sum and difference
frequencies are produced.
For a given setup with only 2 frequencies F1 and F2, frequencies of
all IM products are calculated as follows: F.sub.IM(O)=m F1+/-n F2
(1) where O indicates the order, which is indicated by m+n.
That is, the frequency of lower odd IM products is calculated as
follows:
.times..times..times..times..times..times..times..times..times..times..ti-
mes..times..times..times..times..times..times..function..times..times..tim-
es..times..times..times..times..times. ##EQU00001##
For calculating the upper odd IM products, F1 and F2 have to be
interchanged.
FIG. 2 is a diagram illustrating the lower and upper odd IM
products for illustration purposes.
FIG. 3 illustrates some possible PIM sources. As shown in FIG. 3,
PIM may occur at coax jumpers, cable junctions, cable connectors,
and so on. For example, intermodulation distortions may be caused
by corroded contacts at cable connectors, or the like.
In current FDD network radio equipment, a receiver degradation
caused by passive intermodulation (PIM) problems is guessed today
indirectly via statistical methods (KPI). Once UL (uplink) side
problems are identified, external measurement equipment and on site
tests are necessary to check the root cause of receiver
desensitization.
Currently it is necessary to send service teams in field, rewire
external PIM tester and do measurement in order to analyze site
performance with respect to PIM problems. Standard measurement
methods via e.g., the above mentioned external PIM tester are often
limited to identify all network components causing PIM. The antenna
lineup is composed of different cables, junctions, etc., all
leading to PIM. Therefore, it is important to identify the main
sources to correct the fault. This however, is time and resource
consuming, in particular when aging of components leads to a slowly
decreased PIM performance of a site.
Hence, the currently known solutions are expensive in terms of
extra equipment (CAPEX, capital expenditure) and labour effort
(OPEX, operational expenditure).
SUMMARY OF THE INVENTION
According to the present invention, there are provided a method,
apparatus and a program for detecting intermodulation in broadband
communication affecting receiver sensitivity.
According to an aspect of the present invention, there is provided
a method comprising:
transmitting, at a base station, a first signal at a first centre
frequency and a second signal at a second centre frequency with a
predetermined transmit power,
capturing, at the base station, received signal at a reception
frequency,
obtaining, at the base station, a delay between the transmitted
signal and a passive intermodulation caused received signal.
According to further refinements as defined under the above aspect,
the method further comprises capturing, at the base station, a
combined transmission signal, and predicting, at the base station,
the passive intermodulation caused received signal based on the
combined transmission signal; measuring, at the base station, the
delay between the transmit signal and the passive intermodulation
caused received signal; obtaining, at the base station, the delay
between the transmit signal and the passive intermodulation caused
received signal using correlation; estimating, at the base station,
a fault location within an antenna lineup based on the obtained
delay between the transmit signal and the passive intermodulation
caused received signal and a reference delay between the
transmitted signal and its related received signal; wherein the
reference delay between the transmitted signal and its related
received signal is known in advance; measuring, at the base
station, a received signal power at a reception frequency,
identifying, at the base station, passive intermodulation caused
received signal power components in the received signal power using
non linear modeling, and calculating, at the base station, a
difference between the passive intermodulation caused received
signal power components and the transmit power; wherein the base
station is a frequency division duplex base transceiver
station.
According to another aspect of the present invention, there is
provided an apparatus comprising
a receiver/transmitter configured to communicate with at least
another apparatus,
a memory configured to store computer program code, and
a processor configured to cause the apparatus to perform:
transmitting a first signal at a first centre frequency and a
second signal at a second centre frequency with a predetermined
transmit power,
capturing received signal at a reception frequency,
obtaining a delay between the transmitted signal and a passive
intermodulation caused received signal.
According to further refinements as defined under the above aspect,
the processor is configured to cause the apparatus to further
perform capturing a combined transmission signal, and predicting
the passive intermodulation caused received signal based on the
combined transmission signal; measuring the delay between the
transmit signal and the passive intermodulation caused received
signal; obtaining the delay between the transmit signal and the
passive intermodulation caused received signal using correlation;
estimating a fault location within an antenna lineup based on the
obtained delay between the transmit signal and the passive
intermodulation caused received signal and a reference delay
between the transmitted signal and its related received signal;
wherein the reference delay between the transmitted signal and its
related received signal is known in advance; measuring a received
signal power at a reception frequency, identifying passive
intermodulation caused received signal power components in the
received signal power using non linear modeling, and calculating a
difference between the passive intermodulation caused received
signal power components and the transmit power; wherein the
apparatus is a frequency division duplex base transceiver
station.
According to another aspect of the present invention there is
provided a computer program product comprising code means adapted
to produce steps of any of the methods as described above when
loaded into the memory of a computer.
According to a still further aspect of the invention there is
provided a computer program product as defined above, wherein the
computer program product comprises a computer-readable medium on
which the software code portions are stored.
According to a still further aspect of the invention there is
provided a computer program product as defined above, wherein the
program is directly loadable into an internal memory of the
processing device.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects, features, details and advantages will
become more fully apparent from the following detailed description
of embodiments of the present invention which is to be taken in
conjunction with the appended drawings, in which:
FIG. 1 is a diagram illustrating occurrence of passive
intermodulation in a network.
FIG. 2 is a diagram illustrating the lower and upper odd IM
products for illustration purposes.
FIG. 3 is a schematic overview illustrating some possible PIM
sources.
FIG. 4 is a diagram schematically illustrating transmission
frequencies and the reception frequency according to an embodiment
of the present invention.
FIG. 5 is a diagram illustrating a measured PIM suppression level
over the RX band range according to an embodiment of the present
invention.
FIG. 6 is a diagram illustrating a measured absolute PIM receive
level over the RX band range according to an embodiment of the
present invention
FIG. 7 is a flowchart illustrating processing of the apparatus
according to certain embodiments of the present invention.
FIG. 8 is a block diagram showing an example of an apparatus
according to certain embodiments of the present invention.
DETAILED DESCRIPTION
In the following, embodiments of the present invention are
described by referring to general and specific examples of the
embodiments, wherein the features of the embodiments can be freely
combined with each other unless otherwise described. It is to be
understood, however, that the description is given by way of
example only, and that the described embodiments are by no means to
be understood as limiting the present invention thereto.
In view of the above described problems, it is an idea of the
present invention to detect the passive intermodulation (IM)
frequency term in the uplink connection and to eliminate the effect
thereof.
According to an embodiment of the invention, it is proposed to
search for the place where the cross-talk occurs with the intention
to eliminate the weak spot or spots of the connection or cabling
between the base station and the antenna.
That is, it is proposed to directly use BTS radio resources to
identify the location of passive IMs in an antenna network. The
known TDR (time-domain reflectometry) can be used and also CCR
(cross correlation) with the particularity that the resulting PIM
signal is predicted via appropriate modeling from the transmitted
signal. This yields in a reference for correlation or TDR with the
received PIM.
According to another embodiment of the present invention, it is
proposed to measure the strength of the passive intermodulation
signals. Outlining the place of the problem allows a proper fault
correction e.g. re-cabeling. Channels suffering desensitization
could also either be blocked for communication or the interfered
signal could be deducted from the total received signal as some
kind of PIM interference suppression.
Thus, it is proposed to use the BTS radio resources to directly
measure, over a short period of time, the entire passive
intermodulation performance of the radio cell and to judge
desensitization effects with an application. Such an application
could run centralized in a remotely connected service center.
In the following, methods are described to allow the identification
of critical PIM locations simplifying service field engineers to
correct the fault.
In principle, there are two main concepts to identify transmission
line health conditions, namely, TDR (time domain reflectometry) and
cross correlation method CCR. Both methods are widely used in order
to check VSWR (voltage standing wave ratio) problems with the
antenna lineup.
However, passive intermodulation problems are different in nature
and therefore sites suffering from PIM problems could have no VSWR
issues at all and vice versa. Furthermore, it is noted that VSWR
issues are in downlink direction whereas PIM problems are impacting
the uplink. This leads to the need to measure passive
intermodulation distortion and detecting the location of appearance
independently from VSWR.
In case the TDR approach is used, two pulse like signals on
different frequencies are to be generated from the base transceiver
station and its intermodulation products (IM3, IM5, IM7, etc., as
described above) are to be received. Sending and capturing data is
time synchronized. The delay, and hence, the fault location can be
estimated together with propagation/PIM models within the antenna
lineup.
Instead of measuring directly the time difference, i.e. the delay
between received and estimated/predicted PIM signals, the CCR
approach uses correlation to obtain the delay. Both methods lead
eventually to the place of the PIM appearance.
According to both methods, not only one PIM source can be revealed
in the antenna network, but also several locations can be spotted
as long as PIM power can be measured.
In the following, a measurement principle according to the CCR
distance to fault estimation will be described. Thus, the CCR test
procedure is as follows.
First, two transmission signals at centre frequencies f.sub.1 and
f.sub.2 are identified. As centre frequencies f.sub.1 and f.sub.2,
those frequencies are taken for which the highest PIM P.sub.R is
measured from previous tests and obviously its PIM result is
degrading the receive channel.
Then, two modulated broadband carriers, e.g. LTE5 (WCDMA) with
independent noise characteristic are centered and transmitted at
f.sub.1 and f.sub.2 with maximum or cell specific output power.
Then, the reception signal at f.sub.R and the combined transmission
signal are captured. From the combined transmission signal, the PIM
reception signal is predicted and correlation is used in order to
find dominant PIM echo's.
Then, from calibration and/or hardware design, the basic signal
delay from transmission to reception is known and relative thereto,
the distance to PIM faults in cables/junctions can be predicted
with an expected precision of about 2.5 m or less.
FIG. 4 schematically illustrates frequencies f.sub.1, f.sub.2 and
f.sub.R.
This makes it simpler for service to decide countermeasures and
eliminate, e.g. dominant PIM source by replacing for example an
antenna or cables.
Currently, in order to evaluate PIMs, the classical method using
site portable PIM analyzers is used using a 2 tone approach as
indicated above.
The drawbacks of such solutions are the need for expensive extra
equipment per frequency band. Further, on site support, like e.g.
an extra team, is required that rewires cables and attaches the
analyzer. Rewiring is often already changing the PIM characteristic
of the setup. This solution is typically limited to a TX power of
2.times.43 dBm and to CW signals only which is the classical PIM
tester feature set. Furthermore, in order to detect a main PIM
source, often several measurements and rewiring are necessary.
In the following, a further test procedure according to an aspect
of the present invention will be described.
First, two transmit signals (CW or modulated) at centre frequencies
f.sub.1 and f.sub.2 with transmit power P.sub.t are created. Then,
the received signal power P.sub.R at f.sub.R is measured and the
PIM suppression of the network is calculated. The PIM suppression
calculation is based on an a priori knowledge of the transmission
characteristics and the transmission output power. Further, non
linear modeling and timing information allow identification of PIM
signal components within the receive signal and its receive level
over bandwidth. The difference between the transmission power and
the receive power relative to bandwidth then gives the PIM
suppression value or likewise the signal to interferer
degradation.
The measurement may be repeated with modified transmission
frequencies in order to cover the whole reception channel. Then,
the difference between P.sub.t and P.sub.R over the wanted receive
frequencies can be displayed. The use of modulated signals allows
the identification of own passive intermodulation power and
excludes the influence of spurious emission from e.g. adjacent
cells etc. This is a further advantage against external CW PIM
measurement equipment leading often to wrong results.
FIG. 5 shows a diagram illustrating the measured PIM suppression
level over the RX band range and FIG. 6 shows a diagram
illustrating the measured absolute PIM receive level over a 20 MHz
band III RX band range.
The PIM solution according to an aspect of the present invention is
based on NSN (Nokia Siemens Networks) ASICS/FPGAs
(application-specific integrated circuits/field-programmable gate
arrays) called MAIA/MERA, as an example. Every FDD MAIA/MERA
hardware (HW) design allows broadband capturing of RX data
simultaneously sending of two carriers per pipe. This functionality
realizes superior functionality as every external PIM on site
tester.
According to the above described aspects and embodiments of the
invention, the following advantages can be realized in comparison
to the solutions using external tester.
For example, the existing site equipment, i.e. FDD BTS, can be
directly used and there is no need for expensive extra equipment,
like the external PIM tester. Further, the IM site performance can
be directly seen including active IMs (PA, combiner, predistortion
influence) and passive IMs (antenna, cable, feeder). Further, such
a solution could be remotely controlled and requires less on site
service and thus reduces manual engineering efforts. The TX output
power is the same as used for the site and is not limited by the
power capability of the external PIM tester.
According to the proposed solution, every standard (e.g., GSM, LTE,
WCDMA, etc.) is supported as well as the CW measurement method.
Further, there is no bandwidth limitation and the network IM
suppression capability can be shown as wanted (e.g., IM3, IM5, IM7,
. . . ).
Furthermore, several IM sources and levels can be detected at the
same time and PIM location could be outlined.
Thus, according to the aspects and embodiments of the present
invention as described above, it is possible to measure directly
and remotely controlled, in an installed radio cell, the PIM
behavior/performance of a setup/radio network without the need for
external equipment, like e.g. a PIM tester.
Further, not only the PIM level and the receiver desensitization
can be identified, but also the place of the fault or faults in a
network can be determined, and thus, suitable measures for repair
can be taken.
Furthermore, it is possible to identify the PIM also in presence of
other radiating sources, like e.g. neighbor cell interference.
FIG. 7 is a flowchart illustrating processing of the apparatus
according to certain embodiments of the present invention.
According to an embodiment of the present invention, first, in a
step S71, the apparatus, i.e. the FDD BTS transmits a first signal
at a first centre frequency and a second signal at a second centre
frequency with a predetermined transmit power. Then, in a step S72,
the BTS captures the received signal at a reception frequency, and
then in a step S73, obtains a delay between the transmitted signal
and a passive intermodulation caused received signal.
According to further aspects of the present invention, the BTS
captures a combined transmission signal, and predicts the passive
intermodulation caused received signal based on the combined
transmission signal.
According to still further aspects of the present invention, the
BTS measures the delay between the transmit signal and the passive
intermodulation caused received signal, or obtains the difference
between the transmit signal and the passive intermodulation caused
received signal using correlation.
Then, the BTS estimates a fault location within an antenna lineup
based on the obtained delay between the transmit signal and the
passive intermodulation caused received signal and a reference
delay between the transmitted signal and its related received
signal. The reference delay between the transmitted signal and its
related received signal is known in advance.
Furthermore, according to a further aspect of the invention, the
BTS measures a received signal power at a reception frequency,
identifies passive intermodulation caused received signal power
components in the received signal power using non linear modeling,
and calculates a difference between the passive intermodulation
caused received signal power components and the transmit power.
Non linear modeling is a method or algorithm to predict from a
known transmit signal the appearance of the PIM received signal,
hence a mathematical abstraction to match the physical nature of a
passive intermodulation happening e.g. at a corroded cable
junction. The exactness of this model defines the precision of
later stages like the delay estimation or a following PIM
cancellation approach. Thus a good model comprises a complex non
linear operation or several operations to estimate from the
transmit signal the PIM receive signal.
Merely as an example, it is noted that the simplest IM3 PIM non
linear modeling of a transmit signal Tx could be: PIM
IM3Rx=a*(Tx).sup.3 with a being a real or complex number. Good
models reflecting the PIM are usually much more complex.
The present invention is of course not limited to the above
described modeling example but includes all appropriate
modeling.
FIG. 8 is a block diagram showing an example of an apparatus
according to certain embodiments of the present invention.
As shown in FIG. 8, according to an embodiment of the present
invention, the apparatus 80, i.e. FDD BTS, comprises a
receiver/transmitter 81, a memory 82 and a processor 83. The
receiver/transmitter 81 configured to communicate with at least
another apparatus in the network and to transmit and receive
signals, the memory 82 is configured to store computer program
code, and the processor 83 is configured to cause the apparatus to
perform transmitting a first signal at a first centre frequency and
a second signal at a second centre frequency with a predetermined
transmit power, capturing received signal at a reception frequency,
obtaining a delay between the transmitted signal and a passive
intermodulation caused received signal. Further, the processor 83
is configured to cause the apparatus to perform any of the steps of
the method described above.
In the foregoing exemplary description of the apparatus, only the
units that are relevant for understanding the principles of the
invention have been described using functional blocks. The
apparatus may comprise further units that are necessary for its
respective operation. However, a description of these units is
omitted in this specification. The arrangement of the functional
blocks of the apparatus is not construed to limit the invention,
and the functions may be performed by one block or further split
into sub-blocks.
When in the foregoing description it is stated that the apparatus,
i.e. the MTC device (or some other means) is configured to perform
some function, this is to be construed to be equivalent to a
description stating that a (i.e. at least one) processor or
corresponding circuitry, potentially in cooperation with computer
program code stored in the memory of the respective apparatus, is
configured to cause the apparatus to perform at least the thus
mentioned function. Also, such function is to be construed to be
equivalently implementable by specifically configured circuitry or
means for performing the respective function (i.e. the expression
"unit configured to" is construed to be equivalent to an expression
such as "means for").
For the purpose of the present invention as described herein above,
it should be noted that method steps likely to be implemented as
software code portions and being run using a processor at a network
element (as examples of devices, apparatuses and/or modules
thereof, or as examples of entities including apparatuses and/or
modules therefore), are software code independent and can be
specified using any known or future developed programming language
as long as the functionality defined by the method steps is
preserved; generally, any method step is suitable to be implemented
as software or by hardware without changing the idea of the
embodiments and its modification in terms of the functionality
implemented; method steps and/or devices, units or means likely to
be implemented as hardware components at the above-defined
apparatuses, or any module(s) thereof, (e.g., devices carrying out
the functions of the apparatuses according to the embodiments as
described above) are hardware independent and can be implemented
using any known or future developed hardware technology or any
hybrids of these, such as MOS (Metal Oxide Semiconductor), CMOS
(Complementary MOS), BiMOS (Bipolar MOS), BiCMOS (Bipolar CMOS),
ECL (Emitter Coupled Logic), TTL (Transistor-Transistor Logic),
etc., using for example ASIC (Application Specific IC (Integrated
Circuit)) components, FPGA (Field-programmable Gate Arrays)
components, CPLD (Complex Programmable Logic Device) components or
DSP (Digital Signal Processor) components; devices, units or means
(e.g. the above-defined apparatuses, or any one of their respective
units/means) can be implemented as individual devices, units or
means, but this does not exclude that they are implemented in a
distributed fashion throughout the system, as long as the
functionality of the device, unit or means is preserved; an
apparatus may be represented by a semiconductor chip, a chipset, or
a (hardware) module comprising such chip or chipset; this, however,
does not exclude the possibility that a functionality of an
apparatus or module, instead of being hardware implemented, be
implemented as software in a (software) module such as a computer
program or a computer program product comprising executable
software code portions for execution/being run on a processor; a
device may be regarded as an apparatus or as an assembly of more
than one apparatus, whether functionally in cooperation with each
other or functionally independently of each other but in a same
device housing, for example.
In general, it is to be noted that respective functional blocks or
elements according to above-described aspects can be implemented by
any known means, either in hardware and/or software, respectively,
if it is only adapted to perform the described functions of the
respective parts. The mentioned method steps can be realized in
individual functional blocks or by individual devices, or one or
more of the method steps can be realized in a single functional
block or by a single device.
Generally, any method step is suitable to be implemented as
software or by hardware without changing the idea of the present
invention. Devices and means can be implemented as individual
devices, but this does not exclude that they are implemented in a
distributed fashion throughout the system, as long as the
functionality of the device is preserved. Such and similar
principles are to be considered as known to a skilled person.
Software in the sense of the present description comprises software
code as such comprising code means or portions or a computer
program or a computer program product for performing the respective
functions, as well as software (or a computer program or a computer
program product) embodied on a tangible medium such as a
computer-readable (storage) medium having stored thereon a
respective data structure or code means/portions or embodied in a
signal or in a chip, potentially during processing thereof.
It is noted that the embodiments and general and specific examples
described above are provided for illustrative purposes only and are
in no way intended that the present invention is restricted
thereto. Rather, it is the intention that all variations and
modifications which fall within the scope of the appended claims
are covered.
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